feat(locker): add check for nested calls

app/peerfinder/http.go

@@ -97,7 +97,7 @@ func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 			var requests []*Request
 
-			s.state.Modify(r.Context(), func(ctx context.Context, state *state) error {
+			s.state.Use(r.Context(), func(ctx context.Context, state *state) error {
 				for id, p := range state.peers {
 					fmt.Fprintln(w, "PEER:", id[24:], p.Owner, p.Name)
 				}
@@ -170,7 +170,7 @@ func (s *service) getPending(w http.ResponseWriter, r *http.Request, peerID stri
 	)
 
 	var peer *Peer
-	err := s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	err := s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		var ok bool
 		if peer, ok = state.peers[peerID]; !ok {
 			return fmt.Errorf("peer not found: %s", peerID)
@@ -285,7 +285,7 @@ func (s *service) getResults(w http.ResponseWriter, r *http.Request) {
 	// }
 
 	var requests ListRequest
-	s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		requests = make([]*Request, 0, len(state.requests))
 
 		for _, req := range state.requests {
@@ -306,7 +306,7 @@ func (s *service) getResults(w http.ResponseWriter, r *http.Request) {
 	args := requestArgs(r)
 	args.Requests = requests[:maxResults]
 
-	s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		args.CountPeers = len(state.peers)
 		return nil
 	})
@@ -323,7 +323,7 @@ func (s *service) getResultsForRequest(w http.ResponseWriter, r *http.Request, u
 	)
 
 	var request *Request
-	err := s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	err := s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		request = state.requests[uuid]
 
 		return nil
@@ -430,7 +430,7 @@ func (s *service) postResult(w http.ResponseWriter, r *http.Request, reqID strin
 
 	peerID := r.Form.Get("peer_id")
 
-	err := s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	err := s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		var ok bool
 		if _, ok = state.peers[peerID]; !ok {
 			log.Printf("peer not found: %s\n", peerID)

app/peerfinder/jobs.go

@@ -41,7 +41,7 @@ func (s *service) RefreshJob(ctx context.Context, _ time.Time) error {
 		return err
 	}
 
-	err = s.state.Modify(ctx, func(ctx context.Context, t *state) error {
+	err = s.state.Use(ctx, func(ctx context.Context, t *state) error {
 		for _, peer := range peers {
 			t.peers[peer.ID] = peer
 		}
@@ -88,7 +88,7 @@ func (s *service) cleanPeerJobs(ctx context.Context) error {
 	defer span.End()
 
 	peers := set.New[string]()
-	err := s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	err := s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		for id := range state.peers {
 			peers.Add(id)
 		}
@@ -181,7 +181,7 @@ func (s *service) cleanRequests(ctx context.Context, now time.Time) error {
 
 	// truncate all the request streams
 	for _, streamID := range streamIDs {
-		s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+		s.state.Use(ctx, func(ctx context.Context, state *state) error {
 			return state.ApplyEvents(event.NewEvents(&RequestTruncated{
 				RequestID: streamID,
 			}))

app/peerfinder/service.go

@@ -63,7 +63,7 @@ func (s *service) loadResult(ctx context.Context, request *Request) (*Request, e
 		return request, nil
 	}
 
-	return request, s.state.Modify(ctx, func(ctx context.Context, t *state) error {
+	return request, s.state.Use(ctx, func(ctx context.Context, t *state) error {
 
 		for i := range request.Responses {
 			res := request.Responses[i]
@@ -116,7 +116,7 @@ func (s *service) Run(ctx context.Context) (err error) {
 			}
 		}
 
-		s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+		s.state.Use(ctx, func(ctx context.Context, state *state) error {
 			return state.ApplyEvents(events)
 		})
 		events = events[:0]

cmd/webfinger/webfinger_e2e_test.go

@@ -24,6 +24,7 @@ func TestMain(m *testing.M) {
 	}
 	defer os.RemoveAll(data)
 
+	os.Setenv("EV_DATA", "mem:")
 	os.Setenv("EV_HTTP", "[::1]:61234")
 	os.Setenv("WEBFINGER_DOMAINS", "::1")
 

ev.go

@@ -54,7 +54,7 @@ func Register(ctx context.Context, name string, d driver.Driver) error {
 	ctx, span := lg.Span(ctx)
 	defer span.End()
 
-	return drivers.Modify(ctx, func(ctx context.Context, c *config) error {
+	return drivers.Use(ctx, func(ctx context.Context, c *config) error {
 		if _, set := c.drivers[name]; set {
 			return fmt.Errorf("driver %s already set", name)
 		}

pkg/cron/cron.go

@@ -74,7 +74,7 @@ func (c *cron) NewCron(expr string, task func(context.Context, time.Time) error)
 	c.jobs = append(c.jobs, job)
 }
 func (c *cron) RunOnce(ctx context.Context, once func(context.Context, time.Time) error) {
-	c.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	c.state.Use(ctx, func(ctx context.Context, state *state) error {
 		state.queue = append(state.queue, once)
 		return nil
 	})
@@ -126,7 +126,7 @@ func (c *cron) run(ctx context.Context, now time.Time) {
 	span.AddEvent("Cron Run: " + now.Format(time.RFC822))
 	// fmt.Println("Cron Run: ", now.Format(time.RFC822))
 
-	c.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	c.state.Use(ctx, func(ctx context.Context, state *state) error {
 		run = append(run, state.queue...)
 		state.queue = state.queue[:0]
 

pkg/es/driver/disk-store/disk-store.go

@@ -100,7 +100,7 @@ func (d *diskStore) Open(ctx context.Context, dsn string) (driver.Driver, error)
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
-		l.Modify(ctx, func(ctx context.Context, w *wal.Log) error {
+		l.Use(ctx, func(ctx context.Context, w *wal.Log) error {
 			ctx, span := lg.Span(ctx)
 			defer span.End()
 
@@ -139,7 +139,7 @@ func (d *diskStore) EventLog(ctx context.Context, streamID string) (driver.Event
 
 	el := &eventLog{streamID: streamID, diskStore: d}
 
-	return el, d.openlogs.Modify(ctx, func(ctx context.Context, openlogs *openlogs) error {
+	return el, d.openlogs.Use(ctx, func(ctx context.Context, openlogs *openlogs) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
@@ -193,7 +193,7 @@ func (e *eventLog) Append(ctx context.Context, events event.Events, version uint
 	event.SetStreamID(e.streamID, events...)
 
 	var count uint64
-	err := e.events.Modify(ctx, func(ctx context.Context, l *wal.Log) error {
+	err := e.events.Use(ctx, func(ctx context.Context, l *wal.Log) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
@@ -248,7 +248,7 @@ func (e *eventLog) Read(ctx context.Context, after, count int64) (event.Events,
 
 	var events event.Events
 
-	err := e.events.Modify(ctx, func(ctx context.Context, stream *wal.Log) error {
+	err := e.events.Use(ctx, func(ctx context.Context, stream *wal.Log) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
@@ -330,7 +330,7 @@ func (e *eventLog) ReadN(ctx context.Context, index ...uint64) (event.Events, er
 	)
 
 	var events event.Events
-	err := e.events.Modify(ctx, func(ctx context.Context, stream *wal.Log) error {
+	err := e.events.Use(ctx, func(ctx context.Context, stream *wal.Log) error {
 		var err error
 
 		events, err = readStreamN(ctx, stream, index...)
@@ -352,7 +352,7 @@ func (e *eventLog) FirstIndex(ctx context.Context) (uint64, error) {
 	var idx uint64
 	var err error
 
-	err = e.events.Modify(ctx, func(ctx context.Context, events *wal.Log) error {
+	err = e.events.Use(ctx, func(ctx context.Context, events *wal.Log) error {
 		idx, err = events.FirstIndex()
 		return err
 	})
@@ -371,7 +371,7 @@ func (e *eventLog) LastIndex(ctx context.Context) (uint64, error) {
 	var idx uint64
 	var err error
 
-	err = e.events.Modify(ctx, func(ctx context.Context, events *wal.Log) error {
+	err = e.events.Use(ctx, func(ctx context.Context, events *wal.Log) error {
 		idx, err = events.LastIndex()
 		return err
 	})
@@ -391,7 +391,7 @@ func (e *eventLog) Truncate(ctx context.Context, index int64) error {
 	if index == 0 {
 		return nil
 	}
-	return e.events.Modify(ctx, func(ctx context.Context, events *wal.Log) error {
+	return e.events.Use(ctx, func(ctx context.Context, events *wal.Log) error {
 		if index < 0 {
 			return events.TruncateBack(uint64(-index))
 		}

pkg/es/driver/mem-store/mem-store.go

@@ -49,7 +49,7 @@ func (m *memstore) EventLog(ctx context.Context, streamID string) (driver.EventL
 
 	el := &eventLog{streamID: streamID}
 
-	err := m.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	err := m.state.Use(ctx, func(ctx context.Context, state *state) error {
 		_, span := lg.Span(ctx)
 		defer span.End()
 
@@ -76,7 +76,7 @@ func (m *eventLog) Append(ctx context.Context, events event.Events, version uint
 
 	event.SetStreamID(m.streamID, events...)
 
-	return uint64(len(events)), m.events.Modify(ctx, func(ctx context.Context, stream *event.Events) error {
+	return uint64(len(events)), m.events.Use(ctx, func(ctx context.Context, stream *event.Events) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
@@ -117,7 +117,7 @@ func (m *eventLog) ReadN(ctx context.Context, index ...uint64) (event.Events, er
 	defer span.End()
 
 	var events event.Events
-	err := m.events.Modify(ctx, func(ctx context.Context, stream *event.Events) error {
+	err := m.events.Use(ctx, func(ctx context.Context, stream *event.Events) error {
 		var err error
 
 		events, err = readStreamN(ctx, stream, index...)
@@ -135,7 +135,7 @@ func (m *eventLog) Read(ctx context.Context, after int64, count int64) (event.Ev
 
 	var events event.Events
 
-	err := m.events.Modify(ctx, func(ctx context.Context, stream *event.Events) error {
+	err := m.events.Use(ctx, func(ctx context.Context, stream *event.Events) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 

pkg/es/driver/streamer/streamer.go

@@ -76,7 +76,7 @@ func (s *streamer) Subscribe(ctx context.Context, streamID string, start int64)
 	})
 	sub.unsub = s.delete(streamID, sub)
 
-	return sub, s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	return sub, s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		state.subscribers[streamID] = append(state.subscribers[streamID], sub)
 		return nil
 	})
@@ -85,14 +85,14 @@ func (s *streamer) Send(ctx context.Context, streamID string, events event.Event
 	ctx, span := lg.Span(ctx)
 	defer span.End()
 
-	return s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+	return s.state.Use(ctx, func(ctx context.Context, state *state) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 
 		span.AddEvent(fmt.Sprint("subscribers=", len(state.subscribers[streamID])))
 
 		for _, sub := range state.subscribers[streamID] {
-			err := sub.position.Modify(ctx, func(ctx context.Context, position *position) error {
+			err := sub.position.Use(ctx, func(ctx context.Context, position *position) error {
 				ctx, span := lg.Span(ctx)
 				defer span.End()
 
@@ -128,7 +128,7 @@ func (s *streamer) delete(streamID string, sub *subscription) func(context.Conte
 		if err := ctx.Err(); err != nil {
 			return err
 		}
-		return s.state.Modify(ctx, func(ctx context.Context, state *state) error {
+		return s.state.Use(ctx, func(ctx context.Context, state *state) error {
 			_, span := lg.Span(ctx)
 			defer span.End()
 
@@ -228,7 +228,7 @@ func (s *subscription) Recv(ctx context.Context) <-chan bool {
 		var wait func(context.Context) bool
 		defer close(done)
 
-		err := s.position.Modify(ctx, func(ctx context.Context, position *position) error {
+		err := s.position.Use(ctx, func(ctx context.Context, position *position) error {
 			_, span := lg.Span(ctx)
 			defer span.End()
 
@@ -280,7 +280,7 @@ func (s *subscription) Events(ctx context.Context) (event.Events, error) {
 	defer span.End()
 
 	var events event.Events
-	return events, s.position.Modify(ctx, func(ctx context.Context, position *position) error {
+	return events, s.position.Use(ctx, func(ctx context.Context, position *position) error {
 		ctx, span := lg.Span(ctx)
 		defer span.End()
 

pkg/es/event/reflect.go

@@ -106,7 +106,7 @@ func RegisterName(ctx context.Context, name string, e Event) error {
 
 	span.AddEvent("register: " + name)
 
-	if err := eventTypes.Modify(ctx, func(ctx context.Context, c *config) error {
+	if err := eventTypes.Use(ctx, func(ctx context.Context, c *config) error {
 		_, span := lg.Span(ctx)
 		defer span.End()
 
@@ -124,7 +124,7 @@ func GetContainer(ctx context.Context, s string) Event {
 
 	var e Event
 
-	eventTypes.Modify(ctx, func(ctx context.Context, c *config) error {
+	eventTypes.Use(ctx, func(ctx context.Context, c *config) error {
 		_, span := lg.Span(ctx)
 		defer span.End()
 

pkg/locker/locker.go

@@ -2,6 +2,7 @@ package locker
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -20,12 +21,21 @@ func New[T any](initial *T) *Locked[T] {
 	return s
 }
 
-// Modify will call the function with the locked value
+type ctxKey struct{ name string }
-func (s *Locked[T]) Modify(ctx context.Context, fn func(context.Context, *T) error) error {
+
+// Use will call the function with the locked value
+func (s *Locked[T]) Use(ctx context.Context, fn func(context.Context, *T) error) error {
 	if s == nil {
 		return fmt.Errorf("locker not initialized")
 	}
 
+	key := ctxKey{fmt.Sprintf("%p", s)}
+
+	if value := ctx.Value(key); value != nil {
+		return fmt.Errorf("%w: %T", ErrNested, s)
+	}
+	ctx = context.WithValue(ctx, key, key)
+
 	ctx, span := lg.Span(ctx)
 	defer span.End()
 
@@ -51,7 +61,7 @@ func (s *Locked[T]) Modify(ctx context.Context, fn func(context.Context, *T) err
 func (s *Locked[T]) Copy(ctx context.Context) (T, error) {
 	var t T
 
-	err := s.Modify(ctx, func(ctx context.Context, c *T) error {
+	err := s.Use(ctx, func(ctx context.Context, c *T) error {
 		if c != nil {
 			t = *c
 		}
@@ -60,3 +70,5 @@ func (s *Locked[T]) Copy(ctx context.Context) (T, error) {
 
 	return t, err
 }
+
+var ErrNested = errors.New("nested locker call")

pkg/locker/locker_test.go

@@ -2,6 +2,7 @@ package locker_test
 
 import (
 	"context"
+	"errors"
 	"testing"
 
 	"github.com/matryer/is"
@@ -22,7 +23,7 @@ func TestLocker(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	err := value.Modify(ctx, func(ctx context.Context, c *config) error {
+	err := value.Use(ctx, func(ctx context.Context, c *config) error {
 		c.Value = "one"
 		c.Counter++
 		return nil
@@ -37,7 +38,7 @@ func TestLocker(t *testing.T) {
 
 	wait := make(chan struct{})
 
-	go value.Modify(ctx, func(ctx context.Context, c *config) error {
+	go value.Use(ctx, func(ctx context.Context, c *config) error {
 		c.Value = "two"
 		c.Counter++
 		close(wait)
@@ -47,7 +48,7 @@ func TestLocker(t *testing.T) {
 	<-wait
 	cancel()
 
-	err = value.Modify(ctx, func(ctx context.Context, c *config) error {
+	err = value.Use(ctx, func(ctx context.Context, c *config) error {
 		c.Value = "three"
 		c.Counter++
 		return nil
@@ -60,3 +61,36 @@ func TestLocker(t *testing.T) {
 	is.Equal(c.Value, "two")
 	is.Equal(c.Counter, 2)
 }
+
+func TestNestedLocker(t *testing.T) {
+	is := is.New(t)
+
+	value := locker.New(&config{})
+	other := locker.New(&config{})
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	err := value.Use(ctx, func(ctx context.Context, c *config) error {
+		return value.Use(ctx, func(ctx context.Context, t *config) error {
+			return nil
+		})
+	})
+	is.True(errors.Is(err, locker.ErrNested))
+
+	err = value.Use(ctx, func(ctx context.Context, c *config) error {
+		return other.Use(ctx, func(ctx context.Context, t *config) error {
+			return nil
+		})
+	})
+	is.NoErr(err)
+
+	err = value.Use(ctx, func(ctx context.Context, c *config) error {
+		return other.Use(ctx, func(ctx context.Context, t *config) error {
+			return value.Use(ctx, func(ctx context.Context, x *config) error {
+				return nil
+			})
+		})
+	})
+	is.True(errors.Is(err, locker.ErrNested))
+}